Abstract: In order to optimize the extraction process of fucoxanthin from the Sargassum horneri and the purification research, in this study, fresh Sargassum horneri was used as raw material, ultrasonic-assisted organic solvent extraction method was used, and the extraction process of fucoxanthin was optimized by single factor and response surface methodology (RSM). Subsequently, six different macroporous resins were used to purify fucoxanthin, and the static adsorption and resolution kinetics were studied. The optimized process was obtained: Ethanol concentration of 95%, ultrasound time of 21 min, liquid-to-material ratio of 38:1, extraction times was once, the extraction yield of fucoxanthin obtained was 200.28 μg/g (FW). Through static adsorption and analytical kinetic studies, the results showed that the pseudo-first-order kinetic model could better interpret the kinetic behavior of six resins for fucoxanthin adsorption. Combining the results of dynamic adsorption and analysis, the chromatography resin with the best performance was selected as KP670 type macroporous resin (R²>0.99), and the purity was increased from 0.9% to 31.07%. Experiments proved that the process of extracting and purifying fucoxanthin from fresh Sargassum horneri was feasible.